Banded plastic bag manufacturing method and apparatus

ABSTRACT

An apparatus and method for manufacturing banded plastic bags from a unitary web imprinted with bag faces and bands. The bands are separated from the remainder of the web, accurately positioned relative to the bag faces and secured thereto.

United States Patent [1 1 Finch et al. July 10, 1973 BANDED PLASTIC BAG MANUFACTURING [56] References Cited METHOD AND APPARATUS UNITED STATES PATENTS [75] Inventors: Jerry L. Finch; Donald E. Misner; 2,815,620 12/1957 Prodigo 93/8 WA X James L. Brooks, all of Greenburg, 3,655,475 4/1972 Stelling, Jr. et a1 156/512 X d 1,169,098 1/1916 Thornton 156/512 3,568,576 3/1971 Lehmacher et al 93/33 H [73] Asslgneez Crown Zellerbach Corporation, San

Francisco Primary ExaminerAndrew R. Juhasz [22] Filed: Dec. 13, 1971 Assistant Examiner-James F. Coan An Th R. L t l. 21 Appl. No.: 207,373 was ampe e a [57] ABSTRACT [52] 93/8 93/8 An apparatus and method for manufacturing banded mt Cl 5 plastic bags from a unitary web imprinted with bag Field of Search n 93/35 35 3 3 faces and bands. The bands are separated from the re 93/DlG. 1, 8 W, 8 WA, 34; 156/300, 301, 302, 303, 271, 264, 512, 519

mainder of the web, accurately positioned relative to the bag faces and secured thereto.

6 Claims, 4 Drawing Figures PATENIED JUL 1 0 3. 744.383

41 4. Hi. l] [M3 BANDED PLASTIC BAG MANUFACTURING METHOD AND APPARATUS BACKGROUND OF THE INVENTION This invention relates to the manufacture of banded bags from plastic heat-sealable sheet material, such as Pliofilm and polyolefin film, for example, polyethylene and polypropylene.

In the packaging field increasing usage has been made of promotional advertising bands attached to product bags, such as bread bags. The conventional practice for the manufacture of these banded bags has been for the packager to utilize a multi-stage operation. The bands and the bags normally would be printed separately and converted from separate imprinted roll stock. When applying the bands during the bag manufacturing process from these separate roll stocks it has been extremely difficult to register the bands with the bag faces. Consequently, this conventional prior art approach results in a multi-stage manufacturing process with consequent increased costs and an inferior product.

SUMMARY AND OBJECTS OF THE INVENTION The present invention overcomes the foregoing difficulties by providing a method and apparatus for the manufacture of banded bags wherein a single imprinted web may be utilized to form both the bags and the bands attached thereto. Precisely controlled registry may be maintained between the bands and the bag faces to which they are attached at all times.

Summarizing the present invention, anintegral web of flexible material is longitudinally folded to form juxtaposed sheets, one of such sheets being imprinted with a plurality of bag bands over a first portion thereof and a plurality of bag faces over a second portion thereof. While the web is being transported in a predetermined general direction the first sheet portion is separated from the second sheet portion and the imprinted bands are placed into juxtaposed registry with the bag faces at a predetermined location on the faces. The bands are then attached to the bag faces at the predetermined location. To compensate for the transposition of the imprinted bands relative to the bag faces an adjustable compensator is utilized to insure accurate placement of the bands relative to the bag faces prior to their attachment, said attachment preferably being accomplished simultaneously with the formation of the bags by a sealing knife. In the event the bands are to be used as returnable promotional coupons or the like, perforations are formed therein to facilitate their removal from the bags.

From the preceding it is seen that the invention has as its object, among others, the provision of an im proved method and apparatus for forming bags and bands from a single imprinted web and accurately placing the bands on the bag faces and attaching same.

Other objects will become apparent from the following more detailed description and accompanying drawings in which:

FIG. 1 is a perspective view of a banded bag constructed in accordance with the teachings of thepresent invention and illustrating a portion of the band thereof being removed from the bag by the customer;

FIG. 2 is a fragmentary schematic isometric view of apparatus constructed in accordance with the teachings of the invention;

FIG. 3 is a fragmentary plan view of the apparatus shown in FIG. 2; and

FIG. 4 is a partial, fragmentary, cross-sectional view taken alongthe line 4-4 of FIG. 3.

DETAILED DESCRIPTION OF THE INVENTION Referring now to FIG. 1, a banded bag constructed in accordance with the teachings of the present invention is indicated generally by means of reference numeral 11 and comprises a bag 12 constructed of a heatsealable material, such as polyethylene, and a band 13 formed of like material. Bag 12 comprises an upper bag face 14 and a lower bag face 15 which are secured at the edges thereof by means of a conventional heat seal. The closed end 16 of the bag may be of any suitable construction since the principles of the present invention adapt themselves to a wide variety of bag designs. In the interest of simplicity closed end 16 has been illustrated as being a simple straight fold formed by the overlapping of bag faces 14 and 15 from an integral sheet. It will be appreciated, however, that a square bottom or other suitable bag closed-end construction might be utilized.

Referring now to FIG. 2, a web 20 constructed of flexible heat-scalable material such as polyethylene from which the banded bags are manufactured is illustrated. The web is unwound by conventional mechanism from a parent roll (not shown). The web is moved in a general direction illustrated by direction arrow A with an intermittent motion so that it has periods of rest. Suitable conventional mechanism (not shown) folds the web longitudinally to provide two overlying or juxtaposed sheets or plies 21 and 22. It will be noted that upper sheet 22 is greater in width than lower sheet 21 and comprises a first portion within the general area defined by bracket B which is adapted for subsequent conversion into bag faces and an area generally defined by bracket C which is adapted to be converted into bands attached to said bag faces. It should be noted that the upper web sheet 22 is suitably imprinted in these portions.

As the web is moved along in the direction of arrow A, sheet portion C is separated from sheet portion B by means of a slitter knife 24 which is disposed along the path of movement of upper sheet 22. After being separated from sheet portion B, sheet portion C, which comprises a plurality of bag bands disposed in end-toend fashion, is laterally displaced relative to the sheet portion B by means of rotatable turning arms 25 and 26. Turning arms 25 and 26 are suitably mounted so that they are disposed at an approximately angle to the direction of movement of the imprinted web 20 and in spaced parallel relationship to one another as shown.

After sheet portion C passes around turning arm 26 it should be noted that the printed side of the sheet portion is still facing upwardly while sheet portion C itself has been laterally displaced relative to sheet portion B to a desired degree. Because of this lateral displacement the individual bands comprising sheet portion C are normally out of registry, with respect to the bag faces of sheet portion B. To compensate for this and insure accurate registry of each individual band with respect to each bag face, sheet portion C is directed to a compensator device which insures accurate alignment therebetween. The compensator device comprises a plurality of rollers 28, 29 and 30. Rollers 28 and 29 are joumaled for rotatable movement in fixed end brackets 31 and 32 which maintain rollers 28 and 29 in fixed relation to one another and closely adjacent to the upper surface of sheet portion B. Roller 30 on the other hand is rotatably journaled in a bracket 33 which is threadedly mounted at the ends thereof on a pair of upstanding rotatable threaded members 34 and 35. Through a chain and sprocket arrangement indicated generally by means of reference numeral 36 the bottoms of upstanding threaded members 34 and 35 are interconnected for joint rotatable movement. By means of a handle 37 affixed to the top of threading member 35, the operator can selectively move bracket 33, and hence roller 30, in an up and down direction by virtue of the interaction of the threads of the bracket 33 and upstanding members 34 and 35.

Sheet portion C passes under roller 28 and thence upwardly and over roller 30. Sheet portion C then moves downwardly and under roller 29 into close proximity with sheet portion B at a predetermined location thereon. In some situations it may be desirable to perforate the bag bands so that a portion thereof might be readily removed by the customer for use as a returnable coupon, for example. For this purpose, the apparatus according to the present invention incorporates a perforator mechanism through which sheet portion C passes prior to its attachment to the bag face. For the sake of clarity, perforator device 40 is not shown in FIG. 2 and reference may be had to FIGS. 3 and 4 for details of this particular mechanism. The perforator device 40 includes a plurality of perforator teeth 41 which are mounted in unitary fashion at the end of a solenoid device (not shown) of conventional construction and disposed within housing 42. Perforator teeth 41 are disposed over a plate 43 over which sheet portion C rides thereby maintaining the sheet portion out of engagement with the remainder of the web until the perforation operation is completed. During stoppage of the web in its aforedescribed intermittent movement, the solenoid is actuated to drive teeth 41 into and through sheet portion C thereby forming perforations 44 which may be seen with greatest clarity in FIG. 2. Preferably, the perforator has two lines of perforator teeth mounted in unitary fashion for simultaneous movement by the solenoid. The perforator device thus perforates the trailing edge of one band and the leading edge of the following band simultaneously.

After passing from the perforator device 40, the registered bag faces and bands pass into the final stage of the bag banding operation; namely, the sealing and cutting stage. At this stage, a conventional heat-sealing knife 47 is brought into engagement with the web during the intervals the web is stopped during its intermittent motion. The heated knife 47 passes through sheet portion C, sheet portion B and lower sheet 21 thereby substantially simultaneously forming the bag edges and applying the band thereto. Any suitable conventional mechanism may be utilized to operate the heat-sealing knife. The end result is the finished banded bag; product of FIG. 1 wherein the band is shown as having been partially removed from the bag by the customer.

We claim: I

1. In a method of manufacturing banded bags from heat-scalable flexible material, the improvement comprising:

a. forming an integral web of heat-scalable flexible material longitudinally folded to form two juxtaposed sheets, one of said sheets being imprinted with a plurality of bag bands over a first portion thereof and a plurality of bag faces over a second portion thereof, the other of said sheets and the second portion of said one sheet comprising the material from which the bags are to be formed;

b. transporting said web in a predetermined general direction;

0. separating said first sheet portion from said second sheet portion and said other sheet while maintaining said second sheet portion and said other sheet in juxtaposition;

d. positioning said first sheet portion relative to said second sheet portion during said web transport so that said first sheet portion is juxtaposed relative to said second sheet portion and said imprinted bands are placed into registry with said bag faces at a predetermined location on said faces; and

e. at spaced intervals along said web, heat-sealing said juxtaposed first and second sheet portions and said other sheet in a direction transverse to the direction of movement of said web to form sealed bag side edges and attach said bands to said bag faces.

2. The method of claim 1 wherein the step of positioning said first sheet portion relative to said second sheet portion comprises laterally displacing said first sheet portion relative to said second sheet portion with the bands comprising said first sheet portion remaining integrally connected together in web form and compensating for said lateral displacement to provide for accurate registry between the bands and the bag faces.

3. The method of claim 1 wherein attachment of said bands to said bag faces is effected substantially simultaneously with the formation of said sealed bag edges.

4. The method of claim 1 including the additional step of perforating said bands to facilitate their removal from the bag faces after their attachment thereto.

5. In an apparatus for fabricating banded bags from an imprinted integral web of flexible material longitudinally folded to form juxtaposed sheets, the improvement comprising:

a. means for severing one of said sheets to form a band web comprising a plurality of imprinted bands and an imprinted bag face web comprising a plurality of imprinted bag faces;

b. means for positioning said band web relative to said bag face web so that the imprinted bands are positioned relative to the bag faces with the printing thereof in registry, said positioning means comprising displacement means for laterally displacing said band web relative to said bag face web and compensator means disposed along the path of said band web and accumulating a plurality of bag bands thereon prior to attachment thereof to said bag faces, said compensator means comprising a plurality of spaced rollers which provide transport support for said band web and adjustment means for selectively varying the distance between the rollers and the length of the band web supported by said rollers; and

c. means for'attaching said imprinted bands to said bag faces.

6. The improvement according to claim 5 wherein said attaching means comprises a heat sealing knife. 

1. In a method of manufacturing banded bags from heat-sealable flexible material, the improvement comprising: a. forming an integral web of heat-sealable flexible material longitudinally folded to form two juxtaposed sheets, one of said sheets being imprinted with a plurality of bag bands over a first portion thereof and a plurality of bag faces over a second portion thereof, the other of said sheets and the second portion of said one sheet comprising the material from which the bags are to be formed; b. transporting said web in a predetermined general direction; c. separating said first sheet portion from said second sheet portion and said other sheet while maintaining said second sheet portion and said other sheet in juxtaposition; d. positioning said first sheet portion relative to said second sheet portion during said web transport so that said first sheet portion is juxtaposed relative to said second sheet portion and said imprinted bands are placed into registry with said bag faces at a predetermined location on said faces; and e. at spaced intervals along said web, heat-sealing said juxtaposed first and second sheet portions and said oTher sheet in a direction transverse to the direction of movement of said web to form sealed bag side edges and attach said bands to said bag faces.
 2. The method of claim 1 wherein the step of positioning said first sheet portion relative to said second sheet portion comprises laterally displacing said first sheet portion relative to said second sheet portion with the bands comprising said first sheet portion remaining integrally connected together in web form and compensating for said lateral displacement to provide for accurate registry between the bands and the bag faces.
 3. The method of claim 1 wherein attachment of said bands to said bag faces is effected substantially simultaneously with the formation of said sealed bag edges.
 4. The method of claim 1 including the additional step of perforating said bands to facilitate their removal from the bag faces after their attachment thereto.
 5. In an apparatus for fabricating banded bags from an imprinted integral web of flexible material longitudinally folded to form juxtaposed sheets, the improvement comprising: a. means for severing one of said sheets to form a band web comprising a plurality of imprinted bands and an imprinted bag face web comprising a plurality of imprinted bag faces; b. means for positioning said band web relative to said bag face web so that the imprinted bands are positioned relative to the bag faces with the printing thereof in registry, said positioning means comprising displacement means for laterally displacing said band web relative to said bag face web and compensator means disposed along the path of said band web and accumulating a plurality of bag bands thereon prior to attachment thereof to said bag faces, said compensator means comprising a plurality of spaced rollers which provide transport support for said band web and adjustment means for selectively varying the distance between the rollers and the length of the band web supported by said rollers; and c. means for attaching said imprinted bands to said bag faces.
 6. The improvement according to claim 5 wherein said attaching means comprises a heat sealing knife. 